Dopamine is a neuromediator which participates in controlling motricity, cognitive functions and mood, and is involved in the compensation circuit. Five types of dopaminergic receptors have been cloned (D1-D5) and their levels of expression and cerebral distributions have been analyzed. Among these five types of receptor, at least two types have isoforms (Proc. Natl. Acad. Sci. USA 1998, 95, 7731). Although these five types of dopaminergic receptor are pharmacologically distinct, they have been grouped into 2 subfamilies: the D1 subfamily, which comprises the D1 and D5 receptors, and the D2 subfamily, which comprises the D2, D3 and D4 receptors. It is possible to differentiate the pharmacological action of the D1 and D2 subfamilies, but it is generally difficult to differentiate the function of the various types within each subfamily.
A dysfunction of dopaminergic transmission is involved in the symptomatology of central nervous system disorders such as schizophrenic psychosis (Neuropsychopharmacol. 1988, 1, 179), certain neurodegenerative diseases such as, for example, Parkinson""s disease (Neurodegenerative Diseases; Jolles, G.; Stutzmann, J. M.; Eds; Academic Press, 1994, Chap. 8), depression (J. Clin. Psychiatry, 1998, 59 (Suppl. 5), 60), the dependance on certain substances such as, for example, cocaine, tobacco or alcohol (Cell 1997, 90, 991; Nature 1997, 388, 586). Thus, for example, antagonists of central dopaminergic receptors of the D2 type constitute a conventional and clinically effective approach in the treatment of the positive symptoms of schizophrenic psychosis. However, most of the compounds having such a mechanism of action also induce adverse side effects such as symptoms of Parkinson type (Pharmacotherapy 1996, 16, 160) and/or neuroendocrine disorders (Acta Psychiatr. Scand. 1989, 352, 24).
Mewshaw et al. (Bioorg. Med. Chem. Lett. 1998, 8, 295) have described phenoxyethylamines of formula: 
in which X represents a hydrogen atom, a hydroxyl group, an amino group or a methanesulfonamide group, Y represents a hydrogen atom or a halogen atom and Ar is a phenyl or 2-thienyl group, as being partial agonists of the receptor of the D2 type.
Patents WO 98/08817, U.S. Pat. No. 5,760,070, WO 98/08843 and WO 98/08819 describe, respectively, 4-aminoethoxyindoles and 4-aminoethoxyindolones as being agonists of dopaminergic receptors of the D2 type or inhibitors of the synthesis and release of dopamine.
Unangst et al. (J. Med. Chem. 1997, 40, 4026) have described aryloxyalkylamines of formula: 
in which X represents a n oxygen or sulfur atom or a CH2 group; R1 is a hydrogen or chlorine atom, a hydroxyl or hydroxymethyl group, a nitro group or a hydroxy-carbonyl residue; R2 and R3 represent a hydrogen atom, a halogen atom or a methyl group. These compounds are active on the dopaminergic system, in particular on the receptors of the D4 type, and are potentially useful in the treatment of schizophrenia.
Patent WO 97/23482 describes octahydropyrrolo[1,2-a]-pyrazines of formula: 
in which X represents, inter alia, an oxygen atom; m and n=0, 1, 2 and R1 is an unsubstituted, heterocyclic or non-heterocyclic, polycyclic or non-polycyclic aromatic group. These compounds have affinity for the dopaminergic receptors, in particular for the receptors of the D4 type.
Patents FR 2 702 211, JP 51 048 627, JP 51 052 146, DE 2 450 616 and WO 96/31461 describe 2-[2-(alkoxy)phenoxy]ethylamine derivatives of formula: 
in which R is a C1-C4 alkyl group and R1 represents a 4-benzenebutyl, piperidine-4-methyl or 4-benzamidobutyl chain. These compounds are claimed as being ligands of the receptors of the 5-HT1A subtype (FR 2 702 211 and WO 96/31461) or hypotensive agents and tranquilizers (JP 51 048 627, JP 51 052 146 and DE 2 450 616). Patent EP 707 007 describes arylamines with twofold activity: both antagonist of the receptors of the D2 type, and agonist of the 5-HT1A subtype, and which are useful as antipsychotic agents. The compound EMD-12830 (Drug Data Report 1998, 21) of formula: 
is claimed as an atypical antipsychotic agent (i.e. an agent with a reduced propensity to cause side effects of Parkinson type than the conventional antipsychotic agents).
Patent DE 2 364 685 describes phenoxyalkylamines, in particular N-[2-(2-methoxyphenoxy)ethyl]-3- or -4-pyridylmethanamine, are [sic] claimed as hypotensive agents.
Angstein et al. (J. Med. Chem. 196 5, 8, 356) have described aryloxyalkylamines that are active on the cardiovascular system. Among the compounds described is N-[2-(2-methoxyphenoxy)ethyl]benzenemethanamine.
Goldenberg et al. (Chim. Ther. 1973, 8, 259) have described, inter alia, N-[2-(2-methoxyphenoxy)ethyl-2-benzofuranmethanamines as agents with peripheral vasodilatory properties.
4-Methoxy-3-[2-[(phenylmethyl)amino]ethoxy]phenol is described in J. Labelled Compd. Radiopharm. 1993, 33, 1091 and N-[2-(2-methoxyphenoxy)ethyl]furfurylamine is described in FR 1 336 684.
Patent WO 98/11068 describes 1-(2-pyrimidyl)-4-[(3-aryl)benzyl]piperazines as selective ligands of the receptors of the D4 subtype.
The present invention relates to a novel family of compounds which correspond to the general formula (1) 
The compounds of this invention have antidopaminergic activity, in particular on the receptors of the D2 subfamily. In this respect, the compounds of the invention are useful in the treatment of conditions resulting from dopaminergic hyperactivity, such as schizophrenic symptoms and dependency on certain substances. However, the antagonist activity of the products of the invention on the receptors of the D2 type is exerted only during a transient dopaminergic hyperstimulation. In the absence of dopaminergic hyperactivity, that is to say when the dopamine concentration ranges within proportions that are acceptable for normal functioning of the neuron, the compounds of the invention do not induce dopaminergic hypoactivity. The compounds of the invention are thus useful in the treatment of schizophrenic symptoms and have the advantage of being potentially free of the adverse side effects caused by an excessive blocking of the receptors of the D2 type, such as Parkinsonian symptoms and/or endocrine disorders, at doses that are therapeutically effective for treating schizophrenic psychosis.
The compounds of the invention thus differ from the derivatives of the prior art in their chemical formula and their mechanism of action.